It has been found that in women the threshold for sweating and vasodilatation is higher than in males. Additionally, although in women the mechanism for sweating is slower, and occurs at a later period, it is found that the relative part of sweating that evaporates is higher, so that women evaporate sweat more efficiently (to make up for the lower sweat quantities compared to men). Reduced efficiency of the thermoregulation mechanisms in women is also attributed to the differences in mass, body composition (fat and muscle mass), and physical fitness between the genders. In addition, the physiological changes that occur during the different phases of the menstrual cycle can affect core temperature at rest and thermoregulation. Different reports in literature indicate a decreased thermoregulation capacity in the luteal phase of the menstrual cycle compared to the follicular phase. Apparently, thermoregulation capabilities in exercise are linked to progesterone blood levels, which are influenced by contraceptive pills and with the phase of the menstrual cycle.